The flare rate for each additional 100 resumes is $21.50 and $43.00 altogether
$72.50-$29.50=$43.00
So the 200 additional resumes cost $43
Which means if divide her remaining balance of $43.00 by 2(because she had to pay the flat rate twice for the additional 200 copies)
43.00/2 = $21.50
If you are asking what the additional flat rate is for the extra 200 resumes the answer is $21.50 each